1. Field of the Invention
This invention generally relates to the field of hermetically sealed systems and methods of making of such systems.
2. Description of the Related Art
Electronic and mechanical devices are frequently placed in environments that may damage the components unless some form of protection is provided. For example, some electronic medical devices implanted into a body may be exposed to body fluids that may cause unprotected semiconductor circuits and non-electronic components to fail. Such devices may benefit from a hermetic packaging to limit exposure to these harmful elements. Traditional approaches to creating a protective hermetic package for an implantable medical device generally involve the complete encasement of the silicon or semiconductor components of the device in the hermetic package. Such packages typically utilize a metal such as titanium, or a ceramic material like alumina or zirconia. Various glass materials have also been employed. For example, hermetic cavities have been created to form small vacuum chambers for pressure transducers by bonding silicon components to either silicon or glass. The silicon component is usually fixed into a package with epoxy or soldered into the package. The complete encasement of the silicon component with a separate package adds to the size of the device and also increases its cost.
Similarly, other approaches that have been used for pressure transducers by enclosing the sensor in a metal packaging and coupling the environmental pressure to the sensor through a diaphragm bonded to the packaging. Such approaches place an interface between the environment and the sensor for the electronic components to interact with the environment and to protect the integrity of the device. Such a diaphragm may be made from the same or similar materials as the housing which protects the inner components to facilitates bonding and hermetic sealing of the diaphragm with the housing or protective barrier of the device.